1. Field of the Invention
The invention relates to improvements in circuit design in the field of general purpose input/output (I/O) line usage. More specifically, the invention allows a general purpose I/O line to selectively support different functions, while avoiding interference between those functions.
2. Background Art
Electronic devices typically communicate with other external electronic devices or circuits. To support such communication, electronic devices often have a finite number of general purpose I/O (GPIO) lines. GPIO lines are external communication nodes capable of bidirectional data transfer with external electronic devices or circuits. Such communication nodes take up valuable chip space and increase design and testing costs. Designers must therefore carefully anticipate the number of external devices that are expected to interface with a particular electronic device to ensure a sufficient number of GPIO lines.
Typically, a single GPIO line will serve a single external device. A single dedicated use for a GPIO line simplifies chip and software design, and avoids interference that may occur if the GPIO line is used by a plurality of devices. However, lack of foresight or new technical requirements may result in more external devices than there are GPIO lines. Accordingly, there is a need for improvements in circuit designs in the field of GPIO line usage.